# Periodic motion

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Periodic phenomena or event repeats after certain interval like seasons, motion of planets, swings, pendulum etc. In this module, our focus, however, is the physical movement of particle or body, which shows a pattern recurring after certain fixed time interval.

Representation of periodic motion has a basic pattern, which is repeated at regular intervals. What it means that if we know the basic form (building block), then we can describe the motion by following the pattern again and again.

## Periodic attributes

A periodic motion can be described with respect to different quantities. A given periodic motion can have a host of attributes which may undergo periodic variations. Consider, for example, the case of a pendulum. We can choose any of the attributes like angle (θ), horizontal displacement (x), vertical displacement (y), kinetic energy (K), potential energy (U) etc. The values of these quantities undergo periodic alteration with respect to time. These attributes constitute periodic attributes of the periodic motion.

There are, however, other attributes, which may remain constant during periodic motion. If we consider pendulum executing simple harmonic motion (it is a particular periodic motion), then total mechanical energy of the system is constant and as such is independent of time. Hence, we need to pick appropriate attribute(s) to describe a periodic motion in accordance with problem situation in hand.

## Description of periodic motion

We need a mathematical model to describe periodic motion. For this, we employ certain mathematical functions. The important feature of a periodic function is that its value is repeated after certain interval. We call this interval as “period”. In case, this period refers to time, then the same is called “time period”. Mathematically, a periodic function is defined as :

Periodic motion
A function is said to be periodic if there exists a positive real number “T”, which is independent of “t”, such that $f\left(t+T\right)=f\left(t\right)$ .

The least positive real number “T” (T>0) is known as the fundamental period or simply the period of the function. The “T” is not a unique positive number. All integral multiple of “T” is also the period of the function.

In the context of periodic function, an “aperiodic” function is one, which in not periodic. On the other hand, a function is said to be anti-periodic if :

$f\left(t+T\right)=-f\left(t\right)$

## Example

Problem 1: Prove that " $\mathrm{sin}t$ " is a periodic function. Also find its period.

Solution :

We know that :

$\mathrm{sin}\left(n\pi +t\right)={\left(-1\right)}^{n}\mathrm{sin}t,\phantom{\rule{1em}{0ex}}\text{when “n” is an integer.}$

$\mathrm{sin}\left(n\pi +t\right)=\mathrm{sin}t,\phantom{\rule{1em}{0ex}}\text{when “n” is an even integer.}$

Thus, there exists T>0 such that f(t+T) = f(t). Further “nπ” is independent of “t”. Hence, “ $\mathrm{sin}t$ ” is a periodic function. Its period is the least value, when n = 2 (first even positive integer),

$⇒T=2\pi$

The period of "sine" function is collaborated from the figure also. Note that we can not build a sine curve with a half cycle of period “π” (upper figure). We require a full cycle of “2π” to build a sine curve (lower figure).

where we get a research paper on Nano chemistry....?
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
how did you get the value of 2000N.What calculations are needed to arrive at it
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